It is the copper plate from the wedding of Ollave Norton and Raymond Douglass in 1918. Raymond was born in 1894 and died in 1978, Ollave was born in 1897 and died in 1979. Their whole lives were spent in the Greater New England area.
Before they married, Ollave was a teacher in Nashua, New Hampshire, and after their marriage, they lived in Somerville, Belmont, and Cambridge Massachusetts. Here is a picture of their 50th anniversary party, in 1968. They are on the far left of this picture.
I contacted the owner of their family tree on Ancestry, and she sent me the anniversary picture. Her mother and aunt, Raymond and Ollave's daughters, are still alive and looking forward to having the copper plate back where it belongs. So it is about to make the journey to Rhode Island, a little closer to where it started. I hope the Douglass family will enjoy having this little bit of history.